The present invention relates to a device for transferring rod-like articles, and particularly cigarettes, from a longitudinal rectilinear supply path, which is preferably substantially horizontal, along which the rod-like articles move in their axial direction and are aligned, to a subsequent path which is transverse to the supply path and along which the rod-like articles move in a direction transverse to their axes and are preferably carried by a fluted drum the axis of rotation of which is substantially parallel to the longitudinal rectilinear supply path of the rod-like articles. The transferring device comprises one or more pneumatic pick-up heads, or suction heads, which are adapted each one to carry at least one rod-like article, and are directed parallelly to the longitudinal rectilinear supply path of the said articles. The said suction heads are moved by means of a control device in such a manner as to be maintained always parallel to one another, and to move along a closed circuit path, more particularly an elliptical path which is substantially tangent to the longitudinal rectilinear supply path at a pick-up zone, where each suction head takes up due to suction at least one oncoming rod-like article, while the said elliptical path is contained in a plane which is tangent to the starting point of the subsequent transverse path and more particularly in a plane tangent to a generatrix of the said fluted drum at a delivery zone, where each suction head deposits the rod-like article onto the subsequent transverse path and particularly inside a flute of the said fluted drum.
Transferring devices of the above mentioned type are known, in which there is provided for just one suction head, the closed circuit path of which is contained in a plane substantially vertical and consists of an elliptical path having its major axis substantially horizontal. The pick-up zone of the rod-like articles from the longitudinal rectilinear supply path is located at one extremity of the minor vertical axis of the said elliptical path, while the delivery zone of the articles to the subsequent transverse path, and more particularly to the fluted drum, is located at one extremity of the major horizontal axis of the elliptical path. The mechanism for driving the suction head is realized in such a manner that, at the extremities of the minor axis of the elliptical path and consequently at the pick-up zone of the articles from the horizontal rectilinear supply path, the suction head presents a linear speed which is parallel and substantially equal or slightly greater than the speed of the articles arriving along the longitudinal rectilinear path, while at the extremities of the major axis of the elliptical path, and consequently at the delivery zone, the suction head presents a linear speed parallel and substantially equal to the peripheral speed of the fluted drum.
The above mentioned known-type device presents the advantage that while the suction head moves along the arc of the elliptical path between the pick-up zone and the delivery zone, the horizontal component of the tangential speed of the suction head decreases very gradually, and accordingly the increase of the vertical component of said speed is also gradual. In this manner, and particularly whenever the rod-like articles carried by the mentioned transferring device are cigarettes, damage to the said cigarettes is avoided, and more particularly the dribbling out of tobacco from the cigarette ends is eliminated, thanks to the reduction of the accelerations and decelerations of the suction head and particularly thanks to the graduality of the reduction of the horizontal component of the tangential speed of the suction head itself.
The known device of the above mentioned type presents one single suction head, and consequently can be employed in case of not too high speeds of the rod-like articles arriving on the longitudinal rectilinear supply path. Moreover, the mechanism which is utilized in this known device for the movement of the suction head along an elliptical path, is rather complicated in its construction, which is based on gear trains, and consequently is also noisy.
The purpose of the present invention is to eliminate the above inconveniences, by providing a transferring device of the above described type, which, besides the possibility of presenting a plurality of suction heads and therefore of maintaining within acceptable limits the values of the accelerations and of the decelerations to which the rod-like articles are subjected during their transfer even at higher supply speeds of the said articles along their longitudinal rectilinear path, presents also a more simple and less noisy constructive realization, is less expensive in construction and easier in maintenance.
The mentioned purpose is attained by providing, in accordance with the present invention, a transferring device of the above mentioned type which is substantially characterized by the fact that it comprises two main rotary elements of which one is driven into rotation by suitable driving means, and which are rotatably mounted on two fixed shafts parallel and spaced apart, said main rotary elements being coupled with each other by means of at least one pair of main double cranks consisting each of an arm integral with two opposed crank pins which rotatably engage the two main rotary elements facing each other, so as to form a first rotary system of the articulated parallelogram type, in which the arms of the main double cranks are maintained always parallel to one another, while a crank pin of at least one main double crank is extended beyond the respective main rotary element and terminates with a pin arranged in eccentric position, so as to form a pair of orbiting axes parallel and spaced between each other, onto which there are rotatably mounted two secondary rotary elements coupled between each other by at least one pair of secondary double cranks so as to form a second rotary system of the articulated parallelogram type, the crank pin of at least one secondary double crank extending beyond the respective secondary rotary element so as to form an extension on which there is secured a pneumatic pick-up or suction head, while the other secondary rotary element is driven into rotation and is coupled in such a manner to the fixed main shaft around which it orbits, so as to rotate around intsel upon rotation of the main rotary elements, and more particularly to rotate around itself with an angular speed which is equal but contrary to that of the said pair of main rotary elements.
Preferably, according to one preferred embodiment of the invention, the secondary rotary element driven into rotation is coupled with the fixed shaft around which it orbits, by means of a toothed belt passed around a toothed pulley integral with the said secondary rotary element and passed around a toothed pulley integral with the said fixed shaft and having a diameter double than the diameter of the said first toothed pulley.